[bob_hefley]

With using two transaxles powered from one pump. (From the pump to one motor, out of that motor into the second motor) If the stock pump is used, is travel speed cut in half?

 

[Hydriv]

With using two transaxles powered from one pump. (From the pump to one motor, out of that motor into the second motor) If the stock pump is used, is travel speed cut in half?

Motor speed is related to the GPM of oil pushed through it. By putting the two motors in series, they both see the exact same GPM. If you put them in parallel, then the flow would be divided between the two of them. In that configuration, each motor would see only half of the pump output and max ground speed would be cut in half.

 

[grummy]

If you put them in parallel, then the flow would be divided between the two of them. In that configuration, each motor would see only half of the pump output and max ground speed would be cut in half.

And note, putting them in parallel would likely cut your enjoyment by another 3/4, as doing so will only provide oil to the wheel that will slip the easiest as the oil takes the easier route thru the system. So, drive motors must be connected in series to actually work.

As I plan ahead, I am convinced I do not need or desire my articulated to reach the rocket travel pace of your average 200 series. Its more a traction/workhorse machine. I may at minimum use 400 series motors in 200 axles to slow the pace, or, attempt a two pump system with about a 4gpm pump for the drive and a 6-7gpm pump for the rest. 10-11 gpm total should be a nice fit in the 1/2" lines, but to do so, its at least a 20hp minimum requirement. 24hp would be better.

Does anyone recall the max torque ratings of an 18hp Onan ? I'd like to compare that with the 14hp 2 cylinder diesels we are seeing for under $800 in the surplus market.

 

[boomers_influence]

grummy
my spec. chart shows approx. 31 lb. ft. torque.
boomer

 

[grummy]

grummy
my spec. chart shows approx. 31 lb. ft. torque.
boomer

Thanks Boomer, Now I'll have to try to dig out the torque ratings of those diesels. I think torque ratings are the thing to look at rather than HP when looking at it from a diesel perspective.

 

[whlpny]

Sounds like your question has been answered - groundspeed is unchanged. Now I have a question- In stock form- do the 200 and 400 series tractors have the same ground speed? Where do the differences lie- in the ring gear or the hyd motor output? I am contemplating a new project and need info!

 

[Hydriv]

Sounds like your question has been answered - groundspeed is unchanged. Now I have a question- In stock form- do the 200 and 400 series tractors have the same ground speed? Where do the differences lie- in the ring gear or the hyd motor output? I am contemplating a new project and need info!

In order to answer your question, I need to set some parameters.

- my answer applies only to tractors made after 1970

- there were minor differences in the pumps used in the various 200/400/600 models over the years and those differences in GPM will affect the ground speed slightly.

- there was an optional high range gear that was offered which slowed down the max ground speed but this was either retrofitted by the dealer or tractor owner OR special ordered at the time of purchase.

Taking into account the above, the trans-axle components used on all three series of tractors are identical with the exception of wheel bolt pattern and drive motors used. The 200 series tractors used a drive motor with a smaller internal displacement than the motor used on the 400/600 series and that's how the factory attempted to level the playing field when it came to ground speed. However, if you consult the Operator's Manuals that cover both the 200 and 400 models in a given serial number bracket, you will see that the 200's had a higher ground speed than the 400 models.

As an example, Op Manual 9-7074, which covers 220, 222, 224 and 444 models .....shows the the following.

Low Range 4 MPH for 200 models and 3.7 MPH for the 444

High Range 9.4 MPH for 200 models and 8.7 MPH for the 444

Engine HP in either model plays no part as all of this is based upon 3600 RPM governed engine speed.

Keep in mind that Case and Ingersoll used hydraulic components from many different companies over the years such as Parker, Cessna, Wooster, Barnes etc and while they attempted to spec the size of the pump, it did vary slightly.

If you wanted a low speed, high torque articulated tractor, then you could use trans-axles from the 200 series so that you got the 5 bolt wheel pattern and then change to motors from a 400 series tractor.

Or you could go the other way and select 400 series trans-axles so you had the larger diameter 16" rims/tires and then install 200 series motors that spin faster when the same GPM of oil is applied to them. However, torque would suffer as a result.

Alternatively, you can choose a larger or smaller displacement gear pump to affect the ground speed either up or down. You could also choose to use a hydrostatic pump if you had no intentions of running motorized attachments from the tractor. The hydro pump could be controlled easily with your foot for both direction and infinite ground speed.

 

[whlpny]

Wow- thanks for the numbers and the info! A future build plan is something that resembles a compact 4wd. I want 8-16 tires in the rear, and 6-12's on the front. Just trying to comeup with correct driven speeds so everything works together. I have heard that the ratios are actually different in a big tractor but I don't know how much or if that is actually true. I haven't researched that far yet honestly. it seems that I read in a post somehwere that they turn the front axle faster to allow for differences when the tracor makes sharp turns?? So possibly the variation between a 200 and 400 would be fine. I know i can change the fluid transfer with dividers, but just running scenarios through my head and would value some input!

On a side note- I just recently traded off the new style Toro 4x4 for a Red Brand with a Ark loader and a Brantly backhoe on it. What a fun toy! Some of you may have noticed the Toro went directly to Ebay- It made it up to $5450.00 but didn't hit the res, I was fairly impressed - made me feel good!

 

[Bart]

A future build plan is something that resembles a compact 4wd. I want 8-16 tires in the rear, and 6-12's on the front. Just trying to comeup with correct driven speeds so everything works together.

I don't think that is a good idea, it will be much more complicated trying to get the proper balance in the flow rates for the front and rear drives. If you use matched transaxles and motors for the front and back you just connect the two motors in series and everything will work correctly. To do what you are thinking about you would need a flow divider downstream of the front axle motor to precisely reduce the proportion of flow delivered to the rear axle.

 

[Hydriv]

A future build plan is something that resembles a compact 4wd. I want 8-16 tires in the rear, and 6-12's on the front. Just trying to comeup with correct driven speeds so everything works together.

I don't think that is a good idea, it will be much more complicated trying to get the proper balance in the flow rates for the front and rear drives. If you use matched transaxles and motors for the front and back you just connect the two motors in series and everything will work correctly. To do what you are thinking about you would need a flow divider downstream of the front axle motor to precisely reduce the proportion of flow delivered to the rear axle.

Bart.
He intends to run 16" rubber on the back and 12" on the front. Therefore, he needs a 400 axle in the back and a 200 in the front.

I don't see this as a problem on an articulated unit. If the front wants to go a tad faster, so what? It will just pull the back along. The speed differences, as shown above are not huge. If the front proved to pull too hard, then stick adjustable flow divider between the motors and bleed off a tiny bit of fluid until you "feel" that you have balanced it out. Then set it and forget it.

Thoughts?

 

[cp7]

I would think if you ran 15s instead of 16s that you might speed up the 400 rear to help match it up. Or do I have it backwards? Maybe it would need the 600 series motor with 16s. :headscratcher:

 

[whlpny]

Sorry guys I've not mastered the quote feature yet......
The tractor will actually be front steer- not articulated. I don't think running matched axles is gonna work with the difference in the tire diameters. I have to agree that some pull won't hurt, and flow control should balance it out. I'm just looking for the best configuration of components. 15's on the rear is a possibility but I believe that would be going the wrong way for speed match-up. Thanks for your input- and anymore is welcome- thats why I came here thanks to Tom!

 

[Hydriv]

First things first.

Using 15's would be going in the wrong direction. That would slow the rear down, not speed it up. You want a larger diameter wheel so that you have a longer circumference that will cover more distance per revolution.

All 400's use the exact same drive motor as the 600's, so there is no relief in that direction.


Now.... I am confused. :headscratcher: :headscratcher: :headscratcher: :headscratcher:

If you are going to use two Case trans-axles, how do you make one of them "front steer"? Or are you intending on getting a mechanical front steer axle and then powering it with a hydraulic motor?

 

[whlpny]

Yup- Case front axle- LOTS of machining!! Stay tuned- when I find what I'm after I will show ya!

 

[tanandorange]

Yup- Case front axle- LOTS of machining!! Stay tuned- when I find what I'm after I will show ya!

Have you ever looked at a front axle from a 7020 4wd loader? They use an axle beam made from VERY heavy plate steel with Hilliard components driving the wheels. It may be easier to copy their design using some used ATV CV shafts with heavier homebrew steering knuckles. OR adapt steering knuckles with unitized spindle bearing hubs from a FWD car with shortened CV shafts and mount it all on an axle beam cut from plate with a plasma cutter. The diff could be anything small with a useable ratio. Just throwing ideas around, John

 

[Bart]

[quote="Hydriv
Bart.
He intends to run 16" rubber on the back and 12" on the front. Therefore, he needs a 400 axle in the back and a 200 in the front.

I don't see this as a problem on an articulated unit. If the front wants to go a tad faster, so what? It will just pull the back along. The speed differences, as shown above are not huge. If the front proved to pull too hard, then stick adjustable flow divider between the motors and bleed off a tiny bit of fluid until you "feel" that you have balanced it out. Then set it and forget it.

Thoughts?[/quote]

The speed difference is not insignificant, approx. 10%, but it may work. The geroller motors allow some bypass so there is a little "play" in the system that could compensate for the speed differences so I guess the real question is how much "play" is there? If you were using gear motors with no "play" then the tractor would constantly be skidding some wheels causing a lot of tire wear. This would be less of a problem on turf or dirt but on a solid surface it would be significant. I recall having to rescue my wife one summer day when her SuV "broke"in the Walmart parking lot and the vehicle wouldn't move very well--turned out she had inadvertently engaged the differential locks and making a slight turn made it feel like you were pulling a 10,000 lb trailer up hill.

In any event, I would not build a working tractor that way but for a show tractor you might get by as you suggest.

It would be interesting to know how the 7020 4 WD systems are synchronized as that may provide the answers.

 

[Nutcase446]

Sounds interesting. If you are going to make a Case rear into a steering axle using 12" wheels I would think that you are really going to have to widen it. In the standard configuration there is very little clearance between the wheel and motor. Sounds like you have a plan so I'll say no more. Gregg

 

[tanandorange]

One of these in 1/4 scale would be cool.

 

[Hydriv]

No point going half-way on this project..

Do both axles and make it so it will crab steer, synchro-steer or just front steer.

 

[tanandorange]

No point going half-way on this project..

Do both axles and make it so it will crab steer, synchro-steer or just front steer.

If you're going to do that, then might as well go for the big guns and build a miniature of one of these....

:thumbsup: